コード例 #1
0
    def generate_rho0(self):
        """
        Generate list of density normalizations for the number
        of trials given at initialization. Based on Schoedel
        et al. (2009), assuming M_BH = 4.1x10^6 Msun, gamma=1.0
        """

        rho0ave = 3.2e4  # solar masses/pc^3
        rho0sig = 1.3e4  # solar masses/pc^3

        rho0 = zeros(self.ntrials, dtype=float64)
        gens = aorb.create_generators(1, self.ntrials)
        rho0gen = gens[0]

        for ii in range(self.ntrials):
            rho0[ii] = rho0gen.gauss(rho0ave, rho0sig)

        self.rho0 = rho0
コード例 #2
0
    def generate_rho0(self):
        """
        Generate list of density normalizations for the number
        of trials given at initialization. Based on Schoedel
        et al. (2009), assuming M_BH = 4.1x10^6 Msun, gamma=1.0
        """

        rho0ave = 3.2e4  # solar masses/pc^3
        rho0sig = 1.3e4  # solar masses/pc^3

        rho0 = zeros(self.ntrials, dtype=float64)
        gens = aorb.create_generators(1, self.ntrials)
        rho0gen = gens[0]

        for ii in range(self.ntrials):
            rho0[ii] = rho0gen.gauss(rho0ave, rho0sig)

        self.rho0 = rho0
コード例 #3
0
    def generate(self, efitFile=None):
        """
        Generate the list of masses, distances, and focus positions
        for the number of trials specified at initialization. The 
        resulting variables are arrays of mass, distance, x0, and y0:
        
        m  -- mass in solar masses
        r0 -- distance in pc
        x0 -- X origin in pixels
        y0 -- Y origin in pixels
        
        There are two ways to generate this list:

        1) Use the output from Andrea's efit mass/Ro monte carlos. The
        number of trials spit out by efit must be the same or larger
        than the number of trials specified here. To use this option,
        set the parameter 'efitFile' to the name of the file containing
        the efit monte carlo results.
        
        2) Use a gaussian distribution of mass/Ro/focus position. To
        specify this option (this is the default) just use efitFile=None
        The distributions are determined by the variables:

        self.massCenter    # solar masses
        self.massSigma     # solar masses
        self.distCenter    # parsec
        self.distSigma     # parsec
        self.x0Center      # pixel
        self.x0Sigma       # pixel
        self.y0Center      # pixel
        self.y0Sigma       # pixel

        which should be set after initialization but before calling
        generate(). If no values are specified, the default values from
        the Eisenhauer (2006) paper will be used.
        """

        m = zeros(self.ntrials, dtype=float64)
        r0 = zeros(self.ntrials, dtype=float64)
        x0 = zeros(self.ntrials, dtype=float64)
        y0 = zeros(self.ntrials, dtype=float64)

        if (efitFile == None):
            gens = aorb.create_generators(4, self.ntrials)
            mgen = gens[0]
            r0gen = gens[1]
            x0gen = gens[2]
            y0gen = gens[3]

            for ii in range(self.ntrials):
                m[ii] = mgen.gauss(self.massCenter, self.massSigma)
                r0[ii] = r0gen.gauss(self.distCenter, self.distSigma)
                x0[ii] = x0gen.gauss(self.x0Center, self.x0Sigma)
                y0[ii] = y0gen.gauss(self.y0Center, self.y0Sigma)

        else:
            # Read in M/Ro simluation results
            # Columns are:
            # Dist  x0   y0   a    P  e  t0  w  i  Ome
            # pc    pix  pix  mas  yr    yr
            lines = open(efitFile, 'r').readlines()

            if (self.ntrials > len(lines)):
                print('EFIT file too short for number of trials = ',
                      len(lines))

            for ii in range(self.ntrials):
                fields = lines[ii].split()

                r0[ii] = float(fields[0])  # in pc
                x0[ii] = float(fields[1])  # in pixels
                y0[ii] = float(fields[2])  # in pixels

                # Get the semi-major axis and period in order to get the mass
                a = float(fields[3])  # in mas
                p = float(fields[4])  # in years

                a *= r0[ii] / 1000.0

                # Mass in Msun
                m[ii] = a**3 / p**2

        self.m = m
        self.r0 = r0
        self.x0 = x0
        self.y0 = y0
コード例 #4
0
    def generate(self, efitFile=None):
        """
        Generate the list of masses, distances, and focus positions
        for the number of trials specified at initialization. The 
        resulting variables are arrays of mass, distance, x0, and y0:
        
        m  -- mass in solar masses
        r0 -- distance in pc
        x0 -- X origin in pixels
        y0 -- Y origin in pixels
        
        There are two ways to generate this list:

        1) Use the output from Andrea's efit mass/Ro monte carlos. The
        number of trials spit out by efit must be the same or larger
        than the number of trials specified here. To use this option,
        set the parameter 'efitFile' to the name of the file containing
        the efit monte carlo results.
        
        2) Use a gaussian distribution of mass/Ro/focus position. To
        specify this option (this is the default) just use efitFile=None
        The distributions are determined by the variables:

        self.massCenter    # solar masses
        self.massSigma     # solar masses
        self.distCenter    # parsec
        self.distSigma     # parsec
        self.x0Center      # pixel
        self.x0Sigma       # pixel
        self.y0Center      # pixel
        self.y0Sigma       # pixel

        which should be set after initialization but before calling
        generate(). If no values are specified, the default values from
        the Eisenhauer (2006) paper will be used.
        """

        m = zeros(self.ntrials, dtype=float64)
        r0 = zeros(self.ntrials, dtype=float64)
        x0 = zeros(self.ntrials, dtype=float64)
        y0 = zeros(self.ntrials, dtype=float64)

        if efitFile == None:
            gens = aorb.create_generators(4, self.ntrials)
            mgen = gens[0]
            r0gen = gens[1]
            x0gen = gens[2]
            y0gen = gens[3]

            for ii in range(self.ntrials):
                m[ii] = mgen.gauss(self.massCenter, self.massSigma)
                r0[ii] = r0gen.gauss(self.distCenter, self.distSigma)
                x0[ii] = x0gen.gauss(self.x0Center, self.x0Sigma)
                y0[ii] = y0gen.gauss(self.y0Center, self.y0Sigma)

        else:
            # Read in M/Ro simluation results
            # Columns are:
            # Dist  x0   y0   a    P  e  t0  w  i  Ome
            # pc    pix  pix  mas  yr    yr
            lines = open(efitFile, "r").readlines()

            if self.ntrials > len(lines):
                print "EFIT file too short for number of trials = ", len(lines)

            for ii in range(self.ntrials):
                fields = lines[ii].split()

                r0[ii] = float(fields[0])  # in pc
                x0[ii] = float(fields[1])  # in pixels
                y0[ii] = float(fields[2])  # in pixels

                # Get the semi-major axis and period in order to get the mass
                a = float(fields[3])  # in mas
                p = float(fields[4])  # in years

                a *= r0[ii] / 1000.0

                # Mass in Msun
                m[ii] = a ** 3 / p ** 2

        self.m = m
        self.r0 = r0
        self.x0 = x0
        self.y0 = y0
コード例 #5
0
def run():
    # Assume circular orbits with isotropic normal vectors on circular
    # orbits with circular orbital velocity of 500 km/s.
    ntrials = 10000
    nstars = int((1.0 / 3.0) * 100)
    gens = aorb.create_generators(7, ntrials*10)

    velTot = 500.0  # km/s -- velocity amplitude
    radTot = 2.04   # arcsec

    def fitfunc(p, fjac=None, vx=None, vy=None, vz=None, 
		vxerr=None, vyerr=None, vzerr=None):
        irad = math.radians(p[0])
        orad = math.radians(p[1])
	nx = math.sin(irad) * math.cos(orad)
	ny = -math.sin(irad) * math.sin(orad)
	nz = -math.cos(irad)

	top = (nx*vx + ny*vy + nz*vz)**2
	bot = (nx*vxerr + ny*vyerr + nz*vzerr)**2

	devs = (1.0 / (len(vx) - 1.0)) * top / bot
	status = 0

        return [status, devs.flat]

    # Keep track from every trial the incl, omeg, chi2, number of stars
    incl = na.zeros(ntrials, type=na.Float)
    omeg = na.zeros(ntrials, type=na.Float)
    chi2 = na.zeros(ntrials, type=na.Float)
    niter = na.zeros(ntrials)
    stars = na.zeros(ntrials)

    # Keep track of same stuff for spatial test
    inclPos = na.zeros(ntrials, type=na.Float)
    omegPos = na.zeros(ntrials, type=na.Float)
    chi2Pos = na.zeros(ntrials, type=na.Float)
    niterPos = na.zeros(ntrials)

    angleAvg = na.zeros(ntrials, type=na.Float)
    angleStd = na.zeros(ntrials, type=na.Float)

    for trial in range(ntrials):
	if ((trial % 100) == 0):
	    print 'Trial %d' % trial

	x = na.zeros(nstars, type=na.Float)
	y = na.zeros(nstars, type=na.Float)
	z = na.zeros(nstars, type=na.Float)

	vx = na.zeros(nstars, type=na.Float)
	vy = na.zeros(nstars, type=na.Float)
	vz = na.zeros(nstars, type=na.Float)

	rmag = na.zeros(nstars, type=na.Float)
	vmag = na.zeros(nstars, type=na.Float)
	nx = na.zeros(nstars, type=na.Float)
	ny = na.zeros(nstars, type=na.Float)
	nz = na.zeros(nstars, type=na.Float)
	

	for ss in range(nstars):
	    vx[ss] = gens[0].uniform(-velTot, velTot)
	
	    vyTot = math.sqrt(velTot**2 - vx[ss]**2)
	    vy[ss] = gens[1].uniform(-vyTot, vyTot)
	    
	    vz[ss] = math.sqrt(velTot**2 - vx[ss]**2 - vy[ss]**2)
	    vz[ss] *= gens[2].choice([-1.0, 1.0])
	    
	    x[ss] = gens[3].uniform(-radTot, radTot)

	    yTot = math.sqrt(radTot**2 - x[ss]**2)
	    y[ss] = gens[4].uniform(-yTot, yTot)

	    z[ss] = math.sqrt(radTot**2 - x[ss]**2 - y[ss]**2)
	    z[ss] *= gens[5].choice([-1.0, 1.0])

	    rmag[ss] = math.sqrt(x[ss]**2 + y[ss]**2 + z[ss]**2)
	    vmag[ss] = math.sqrt(vx[ss]**2 + vy[ss]**2 + vz[ss]**2)

	    rvec = [x[ss], y[ss], z[ss]]
	    vvec = [vx[ss], vy[ss], vz[ss]]
	    tmp = util.cross_product(rvec, vvec)
	    tmp /= rmag[ss] * vmag[ss]
	    nx[ss] = tmp[0]
	    ny[ss] = tmp[1]
	    nz[ss] = tmp[2]
	    
	r2d = na.hypot(x, y)
	v2d = na.hypot(vx, vy)
	top = (x * vy - y * vx)
	jz = (x * vy - y * vx) / (r2d * v2d)

	djzdx = (vy * r2d * v2d - (top * v2d * x / r2d)) / (r2d * v2d)**2
	djzdy = (-vx * r2d * v2d - (top * v2d * y / r2d)) / (r2d * v2d)**2
	djzdvx = (-y * r2d * v2d - (top * r2d * vx / v2d)) / (r2d * v2d)**2
	djzdvy = (x * r2d * v2d - (top * r2d * vy / v2d)) / (r2d * v2d)**2
	
	xerr = na.zeros(nstars, type=na.Float) + 0.001 # arcsec
	yerr = na.zeros(nstars, type=na.Float) + 0.001
	vxerr = na.zeros(nstars, type=na.Float) + 10.0  # km/s
	vyerr = na.zeros(nstars, type=na.Float) + 10.0
	vzerr = na.zeros(nstars, type=na.Float) + 30.0 # km/s
	
	jzerr = na.sqrt((djzdx*xerr)**2 + (djzdy*yerr)**2 + 
			(djzdvx*vxerr)**2 + (djzdvy*vyerr)**2)

	# Eliminate all stars with jz > 0 and jz/jzerr < 2
	# I think these are they cuts they are doing
	idx = (na.where((jz < 0) & (na.abs(jz/jzerr) > 2)))[0]
	#idx = (na.where(jz < 0))[0]
	#idx = range(len(jz))

	cotTheta = vz / na.sqrt(vx**2 + vy**2)
	phi = na.arctan2(vy, vx)

	# Initial guess:
	p0 = na.zeros(2, type=na.Float)
	p0[0] = gens[5].uniform(0.1, 90)     # deg -- inclination
	p0[1] = gens[6].uniform(0.1, 360)     # deg -- omega

	# Setup properties of each free parameter.
	parinfo = {'relStep':10.0, 'step':10.0, 'fixed':0, 
		   'limits':[0.0,360.0],
		   'limited':[1,1], 'mpside':1}
	pinfo = [parinfo.copy() for i in range(len(p0))]

	pinfo[0]['limits'] = [0.0, 180.0]
	pinfo[1]['limits'] = [0.0, 360.0]

	# Stuff to pass into the fit function
	functargs = {'vx': vx[idx], 'vy': vy[idx], 'vz': vz[idx],
		     'vxerr':vxerr[idx], 'vyerr':vyerr[idx], 'vzerr':vzerr[idx]}

	m = mpfit.mpfit(fitfunc, p0, functkw=functargs, parinfo=pinfo,
			quiet=1)
	if (m.status <= 0): 
	    print 'error message = ', m.errmsg

	p = m.params

	incl[trial] = p[0]
	omeg[trial] = p[1]
	stars[trial] = len(idx)
	chi2[trial] = m.fnorm / (stars[trial] - len(p0))
	niter[trial] = m.niter
	
	n = [math.sin(p[0]) * math.cos(p[1]),
	     -math.sin(p[0]) * math.sin(p[1]),
	     -math.cos(p[0])]

	# Now look at the angle between the best fit normal vector
	# from the velocity data and the true r cross v normal vector.
	# Take the dot product between n and nreal.
	angle = na.arccos(n[0]*nx + n[1]*ny + n[2]*nz)
	angle *= (180.0 / math.pi)

	# What is the average angle and std angle
	angleAvg[trial] = angle.mean()
	angleStd[trial] = angle.stddev()

# 	print chi2[trial], chi2Pos[trial], incl[trial], inclPos[trial], \
# 	    omeg[trial], omegPos[trial], niter[trial], niterPos[trial]
# 	print angleAvg[trial], angleStd[trial]
	

    # Plot up chi2 for v-fit vs. chi2 for x-fit
    pylab.clf()
    pylab.semilogx(chi2, angleAvg, 'k.')
    pylab.errorbar(chi2, angleAvg, fmt='k.', yerr=angleStd)
    pylab.xlabel('Chi^2')
    pylab.ylabel('Angle w.r.t. Best Fit')
    foo = raw_input('Contine?')

    # Probability of encountering solution with chi^2 < 2
    idx = (na.where(chi2 < 2.0))[0]
    print 'Prob(chi^2 < 2) = %5.3f ' % (len(idx) / float(ntrials))

    # Probability of encountering solution with chi^2 < 2 AND 
    # inclination = 20 - 30 and Omega = 160 - 170
    foo = (na.where((chi2 < 2.0) & (incl > 20) & (incl < 40)))[0]
    print 'Prob of chi2 and incl = %5.3f' % (len(foo) / float(ntrials))

    pylab.clf()
    pylab.subplot(2, 2, 1)
    pylab.hist(chi2, bins=na.arange(0, 10, 0.5))
    pylab.xlabel('Log Chi^2')

    pylab.subplot(2, 2, 2)
    pylab.hist(incl[idx])
    pylab.xlabel('Inclination for Chi^2 < 2')
    rng = pylab.axis()
    pylab.axis([0, 180, rng[2], rng[3]])

    pylab.subplot(2, 2, 3)
    pylab.hist(omeg[idx])
    pylab.xlabel('Omega for Chi^2 < 2')
    rng = pylab.axis()
    pylab.axis([0, 360, rng[2], rng[3]])

    pylab.subplot(2, 2, 4)
    pylab.hist(stars[idx])
    pylab.xlabel('Nstars for Chi^2 < 2')
    rng = pylab.axis()
    pylab.axis([0, 33, rng[2], rng[3]])

    pylab.savefig('diskTest.png')
    
    # Pickle everything
    foo = {'incl': incl, 'omeg': omeg, 'star': stars, 
	   'chi2': chi2, 'niter': niter}

    pickle.dump(foo, open('diskTestSave.pick', 'w'))
コード例 #6
0
def run():
    # Assume circular orbits with isotropic normal vectors on circular
    # orbits with circular orbital velocity of 500 km/s.
    ntrials = 10000
    nstars = int((1.0 / 3.0) * 100)
    gens = aorb.create_generators(7, ntrials*10)

    velTot = 500.0  # km/s -- velocity amplitude
    radTot = 2.04   # arcsec

    def fitfunc(p, fjac=None, vx=None, vy=None, vz=None, 
		vxerr=None, vyerr=None, vzerr=None):
        irad = math.radians(p[0])
        orad = math.radians(p[1])
	nx = math.sin(irad) * math.cos(orad)
	ny = -math.sin(irad) * math.sin(orad)
	nz = -math.cos(irad)

	top = (nx*vx + ny*vy + nz*vz)**2
	bot = (nx*vxerr + ny*vyerr + nz*vzerr)**2

	devs = (1.0 / (len(vx) - 1.0)) * top / bot
	status = 0

        return [status, devs.flat]

    # Keep track from every trial the incl, omeg, chi2, number of stars
    incl = na.zeros(ntrials, type=na.Float)
    omeg = na.zeros(ntrials, type=na.Float)
    chi2 = na.zeros(ntrials, type=na.Float)
    niter = na.zeros(ntrials)
    stars = na.zeros(ntrials)

    # Keep track of same stuff for spatial test
    inclPos = na.zeros(ntrials, type=na.Float)
    omegPos = na.zeros(ntrials, type=na.Float)
    chi2Pos = na.zeros(ntrials, type=na.Float)
    niterPos = na.zeros(ntrials)

    angleAvg = na.zeros(ntrials, type=na.Float)
    angleStd = na.zeros(ntrials, type=na.Float)

    for trial in range(ntrials):
	if ((trial % 100) == 0):
	    print('Trial %d' % trial)

	x = na.zeros(nstars, type=na.Float)
	y = na.zeros(nstars, type=na.Float)
	z = na.zeros(nstars, type=na.Float)

	vx = na.zeros(nstars, type=na.Float)
	vy = na.zeros(nstars, type=na.Float)
	vz = na.zeros(nstars, type=na.Float)

	rmag = na.zeros(nstars, type=na.Float)
	vmag = na.zeros(nstars, type=na.Float)
	nx = na.zeros(nstars, type=na.Float)
	ny = na.zeros(nstars, type=na.Float)
	nz = na.zeros(nstars, type=na.Float)
	

	for ss in range(nstars):
	    vx[ss] = gens[0].uniform(-velTot, velTot)
	
	    vyTot = math.sqrt(velTot**2 - vx[ss]**2)
	    vy[ss] = gens[1].uniform(-vyTot, vyTot)
	    
	    vz[ss] = math.sqrt(velTot**2 - vx[ss]**2 - vy[ss]**2)
	    vz[ss] *= gens[2].choice([-1.0, 1.0])
	    
	    x[ss] = gens[3].uniform(-radTot, radTot)

	    yTot = math.sqrt(radTot**2 - x[ss]**2)
	    y[ss] = gens[4].uniform(-yTot, yTot)

	    z[ss] = math.sqrt(radTot**2 - x[ss]**2 - y[ss]**2)
	    z[ss] *= gens[5].choice([-1.0, 1.0])

	    rmag[ss] = math.sqrt(x[ss]**2 + y[ss]**2 + z[ss]**2)
	    vmag[ss] = math.sqrt(vx[ss]**2 + vy[ss]**2 + vz[ss]**2)

	    rvec = [x[ss], y[ss], z[ss]]
	    vvec = [vx[ss], vy[ss], vz[ss]]
	    tmp = util.cross_product(rvec, vvec)
	    tmp /= rmag[ss] * vmag[ss]
	    nx[ss] = tmp[0]
	    ny[ss] = tmp[1]
	    nz[ss] = tmp[2]
	    
	r2d = na.hypot(x, y)
	v2d = na.hypot(vx, vy)
	top = (x * vy - y * vx)
	jz = (x * vy - y * vx) / (r2d * v2d)

	djzdx = (vy * r2d * v2d - (top * v2d * x / r2d)) / (r2d * v2d)**2
	djzdy = (-vx * r2d * v2d - (top * v2d * y / r2d)) / (r2d * v2d)**2
	djzdvx = (-y * r2d * v2d - (top * r2d * vx / v2d)) / (r2d * v2d)**2
	djzdvy = (x * r2d * v2d - (top * r2d * vy / v2d)) / (r2d * v2d)**2
	
	xerr = na.zeros(nstars, type=na.Float) + 0.001 # arcsec
	yerr = na.zeros(nstars, type=na.Float) + 0.001
	vxerr = na.zeros(nstars, type=na.Float) + 10.0  # km/s
	vyerr = na.zeros(nstars, type=na.Float) + 10.0
	vzerr = na.zeros(nstars, type=na.Float) + 30.0 # km/s
	
	jzerr = na.sqrt((djzdx*xerr)**2 + (djzdy*yerr)**2 + 
			(djzdvx*vxerr)**2 + (djzdvy*vyerr)**2)

	# Eliminate all stars with jz > 0 and jz/jzerr < 2
	# I think these are they cuts they are doing
	idx = (na.where((jz < 0) & (na.abs(jz/jzerr) > 2)))[0]
	#idx = (na.where(jz < 0))[0]
	#idx = range(len(jz))

	cotTheta = vz / na.sqrt(vx**2 + vy**2)
	phi = na.arctan2(vy, vx)

	# Initial guess:
	p0 = na.zeros(2, type=na.Float)
	p0[0] = gens[5].uniform(0.1, 90)     # deg -- inclination
	p0[1] = gens[6].uniform(0.1, 360)     # deg -- omega

	# Setup properties of each free parameter.
	parinfo = {'relStep':10.0, 'step':10.0, 'fixed':0, 
		   'limits':[0.0,360.0],
		   'limited':[1,1], 'mpside':1}
	pinfo = [parinfo.copy() for i in range(len(p0))]

	pinfo[0]['limits'] = [0.0, 180.0]
	pinfo[1]['limits'] = [0.0, 360.0]

	# Stuff to pass into the fit function
	functargs = {'vx': vx[idx], 'vy': vy[idx], 'vz': vz[idx],
		     'vxerr':vxerr[idx], 'vyerr':vyerr[idx], 'vzerr':vzerr[idx]}

	m = mpfit.mpfit(fitfunc, p0, functkw=functargs, parinfo=pinfo,
			quiet=1)
	if (m.status <= 0): 
	    print('error message = ', m.errmsg)

	p = m.params

	incl[trial] = p[0]
	omeg[trial] = p[1]
	stars[trial] = len(idx)
	chi2[trial] = m.fnorm / (stars[trial] - len(p0))
	niter[trial] = m.niter
	
	n = [math.sin(p[0]) * math.cos(p[1]),
	     -math.sin(p[0]) * math.sin(p[1]),
	     -math.cos(p[0])]

	# Now look at the angle between the best fit normal vector
	# from the velocity data and the true r cross v normal vector.
	# Take the dot product between n and nreal.
	angle = na.arccos(n[0]*nx + n[1]*ny + n[2]*nz)
	angle *= (180.0 / math.pi)

	# What is the average angle and std angle
	angleAvg[trial] = angle.mean()
	angleStd[trial] = angle.stddev()

# 	print chi2[trial], chi2Pos[trial], incl[trial], inclPos[trial], \
# 	    omeg[trial], omegPos[trial], niter[trial], niterPos[trial]
# 	print angleAvg[trial], angleStd[trial]
	

    # Plot up chi2 for v-fit vs. chi2 for x-fit
    pylab.clf()
    pylab.semilogx(chi2, angleAvg, 'k.')
    pylab.errorbar(chi2, angleAvg, fmt='k.', yerr=angleStd)
    pylab.xlabel('Chi^2')
    pylab.ylabel('Angle w.r.t. Best Fit')
    foo = input('Contine?')

    # Probability of encountering solution with chi^2 < 2
    idx = (na.where(chi2 < 2.0))[0]
    print('Prob(chi^2 < 2) = %5.3f ' % (len(idx) / float(ntrials)))

    # Probability of encountering solution with chi^2 < 2 AND 
    # inclination = 20 - 30 and Omega = 160 - 170
    foo = (na.where((chi2 < 2.0) & (incl > 20) & (incl < 40)))[0]
    print('Prob of chi2 and incl = %5.3f' % (len(foo) / float(ntrials)))

    pylab.clf()
    pylab.subplot(2, 2, 1)
    pylab.hist(chi2, bins=na.arange(0, 10, 0.5))
    pylab.xlabel('Log Chi^2')

    pylab.subplot(2, 2, 2)
    pylab.hist(incl[idx])
    pylab.xlabel('Inclination for Chi^2 < 2')
    rng = pylab.axis()
    pylab.axis([0, 180, rng[2], rng[3]])

    pylab.subplot(2, 2, 3)
    pylab.hist(omeg[idx])
    pylab.xlabel('Omega for Chi^2 < 2')
    rng = pylab.axis()
    pylab.axis([0, 360, rng[2], rng[3]])

    pylab.subplot(2, 2, 4)
    pylab.hist(stars[idx])
    pylab.xlabel('Nstars for Chi^2 < 2')
    rng = pylab.axis()
    pylab.axis([0, 33, rng[2], rng[3]])

    pylab.savefig('diskTest.png')
    
    # Pickle everything
    foo = {'incl': incl, 'omeg': omeg, 'star': stars, 
	   'chi2': chi2, 'niter': niter}

    pickle.dump(foo, open('diskTestSave.pick', 'w'))